I have the same problem as Luke, with my 798ci HD SI, Unlike Luke my 798 has a internal GPS. I don't troll, so slow speed is not my concern, but I have trouble guiding my boat icon over the icons that mark brush piles. It's like trying to hit a target with a gun barrel that some one keeps jerking around. If you are one in many that thank you have a GPS problem, Try this..... With your boat parked at home, turn on the unit, go to full display of chart ( map ) make sure you have the trail mark '' ON ''. Zoom all the way in . Your boat icon will stay in the center of the display, But you can check the accuracy of the GPS by watching for trail marks as the GPS updates. Most of my long marks are North to South, I am guessing 10 to 20 feet error. and shorter marks East and west ???? ( with display set at North up ) also shows a speed of 0 to I.5 MPH changing ever few seconds as it updates. I am thanking about getting a 899, but now not so sure.

zztop wrote:I have the same problem as Luke, with my 798ci HD SI, Unlike Luke my 798 has a internal GPS. I don't troll, so slow speed is not my concern, but I have trouble guiding my boat icon over the icons that mark brush piles. It's like trying to hit a target with a gun barrel that some one keeps jerking around. If you are one in many that thank you have a GPS problem, Try this..... With your boat parked at home, turn on the unit, go to full display of chart ( map ) make sure you have the trail mark '' ON ''. Zoom all the way in . Your boat icon will stay in the center of the display, But you can check the accuracy of the GPS by watching for trail marks as the GPS updates. Most of my long marks are North to South, I am guessing 10 to 20 feet error. and shorter marks East and west ???? ( with display set at North up ) also shows a speed of 0 to I.5 MPH changing ever few seconds as it updates. I am thanking about getting a 899, but now not so sure.

If you can figure out how to make the satellites stop orbiting the Earth, then you can fix the wandering position curser. The satellite movement is what the unit sees as travel while you are motionless.
Humminbird and Lowrance units don't have an averaging feature to limit that. Some handhelds do.

I just found the AS GPS HS on the Humminbird products page. claims to be accurate to 2.5 meters. MY 798 is generally within about 3 meters. so don't think this external precision GPS is worth the extra expense to me, but may be for better slow speed accuracy. Thanks, with this new info. just decided to buy a 899.